JPH074777B2 - Three-dimensional movement mechanism - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a three-dimensional motion mechanism that can be arbitrarily positioned in a three-dimensional space, and particularly to a leg mechanism of a wall-walking robot and a gravity direction. The present invention relates to a three-dimensional movement mechanism suitable for an arm mechanism of a manipulator installed.

(Prior Art) When inspecting or cleaning a wall surface of a large building such as a building or an oil tank, a wall surface moving device that can move along the wall surface is used. There are various types of wall surface moving devices, and some wall surface suction moving machines that move while suctioning on a wall surface have been proposed so far. The main ones are those that use a plurality of wall adsorption units that perform negative pressure adsorption or magnetic adsorption, and move by sliding the body while repeating adsorption and desorption alternately, or adsorption on the wall by the rotation of adsorption wheels. While moving, etc.

(Problems to be Solved by the Invention) However, in such a wall suction moving machine, even if it is possible to move on a flat vertical wall surface, a cylindrical surface, or a spherical wall surface, it is possible to move across a corner of a building. It is not possible to achieve movements on various wall surfaces such as movements on walls with large projections or movements from the wall to the ceiling.

In order to be able to deal with such various wall surfaces, it is considered that the walking robot has a plurality of sets of leg mechanisms attached to the body. In that case, the leg mechanism is required to have a three-dimensional motion. That is, it is necessary to have at least three degrees of freedom.

As a motion mechanism having such three degrees of freedom, there is, for example, a three-axis orthogonal coordinate type mechanism using three sets of orthogonal actuators. However, in the case of a wall-walking robot that basically moves up a wall, a large load is applied in the direction of gravity. Therefore, when using a three-axis Cartesian coordinate type leg mechanism, an actuator in the direction of gravity is used. It is necessary to increase the output of. Moreover, depending on the posture, a large load is also applied to other actuators, so that the output of those actuators must also be increased. Therefore, each actuator becomes large and the leg mechanism itself becomes extremely heavy.

There is also a joint type three-degree-of-freedom motion mechanism, but when such a mechanism is used as a leg mechanism of a wall-walking robot, it is necessary to generate a large torque at each joint arranged in series. . Therefore, the weight of the leg mechanism also increases.

As described above, since the wall-walking robot basically moves vertically up the wall, it is necessary to reduce its own weight and increase the leg output. Therefore, the conventional three-degree-of-freedom motion mechanism, that is, the three-dimensional motion mechanism has a low feasibility as a leg mechanism of a wall-walking robot.

The present invention has been made in view of such circumstances, and an object thereof is to obtain a three-dimensional motion mechanism suitable for a leg mechanism of a wall-walking robot.

That is, an object of the present invention is to obtain a three-dimensional motion mechanism that is lightweight and can generate high output.

(Means for Solving the Problem) In order to achieve this object, according to the present invention, a parallel link system in which three telescopic actuators are used in parallel is used.
The dimensional movement mechanism is configured. The three telescopic actuators are arranged parallel to each other or at a small angle. The base end is rotatably connected to three different points on the base body, and the tip end is rotatably connected to three different points on the free end frame. The free end frame is fitted to a support rod connected to the base body via a universal joint, and is not rotatable about its axis but is slidably supported in the axial direction. An effector unit such as a wall suction unit is attached to the free end frame.

(Operation) With this configuration, when the three actuators are respectively activated and the lengths thereof are changed, the three-dimensional position of the free end frame changes. In that case, the free-end frame is fitted to the support rod and is allowed to slide only in the axial direction, so that its posture is uniquely determined. Therefore, by appropriately setting the lengths of the three actuators, it is possible to position the effector unit attached to the free end frame at a desired position in the three-dimensional space.

In that case, the three actuators are arranged along the direction of gravity as much as possible in the normal movement posture. By doing so, the load acting on the movement mechanism is almost evenly shared by the three actuators. Moreover, the bending moment applied to the motion mechanism is supported by the support rods into which the free end frames are slidably fitted. Therefore, each actuator can be made to have a small output while giving a sufficient degree of freedom of movement, and the weight of the entire movement mechanism can be reduced.

(Examples) Examples of the present invention will be described below with reference to the drawings.

In the drawings, FIGS. 1 and 2 are a schematic front view and a side view showing an embodiment of a wall-walking robot using a three-dimensional motion mechanism according to the present invention as a leg mechanism, and FIGS. 3 and 4 are legs of the robot. It is a perspective view and a vertical side view of a mechanism.

As shown in FIGS. 1 and 2, the wall-walking robot 1 includes a body 2 as a base body and four sets of leg mechanisms 3, 3, ... Attached to the body 2. Each leg mechanism 3
A wall surface adsorption unit 5, which is an effector unit for adsorbing to the wall surface 4, is attached to the tip of the.

As is clear from FIGS. 3 and 4, the leg mechanism 3 includes three telescopic actuators 6, 6, 6. Each actuator 6 is a ball screw type driven by a motor 7, and its length can be changed independently. The base ends of these three actuators 6, 6, 6 are respectively provided at three points which are not on a straight line of the body 2 via a ball joint 8 or a universal joint.
Is rotatably connected to. Further, the tip end thereof is rotatably connected to a free end frame, that is, a leg frame 10 via ball joints 9 or universal joints at three points which are not on a straight line. Moreover, these actuators 6, 6, 6 are arranged parallel to each other or at a small angle.

A spline shaft 11 is fixed to the leg frame 10. On the other hand, a base end of a support rod 12 is rotatably supported on the body 2 via a universal joint 13. Then, the support rod 12 and the spline shaft 11 of the leg frame 10
And are splined together. Thus, the leg frame
Although not rotatable about the axis of the support rod 12, 10 is supported so as to be slidable in the axial direction.

The wall suction unit 5 includes a support arm 14 and a suction plate 15 attached to the tip thereof. The suction plate 15 is attracted to the wall surface 4 by magnetic force or negative pressure, and as shown in FIG. 5, an elastic body such as rubber is provided by a cap-shaped supporting force generating member 14a provided at the tip of the arm 14. 16
Is supported through. A friction member 14b such as hard rubber is attached to the peripheral portion of the supporting force generating member 14a,
When the suction disk 15 is adsorbed on the wall surface 4 and a shearing force acts on the wall surface 4, the shearing force is supported by the friction member 14b having abrasion resistance and large frictional force.
Only the force that pulls it off acts on the 5.

On the other hand, the base end side of the support arm 14 is a bifurcated branch arm portion.
A base end of a V-arm 17 having 17a, 17a is rotatably connected via a ball joint 18. A coil spring 14s is provided between the support arm 14 and the V arm 17 so that the support arm 14 faces a certain direction with respect to the V arm 17 unless an external force acts. The V arm 17 is rotatably supported by the tip of the leg frame 10 via a universal joint 19. The universal joint 19 is a V arm 17
It allows rotation in two degrees of freedom around the axis of the base end of the ball and around the axis orthogonal to the axis, and the center of rotation is made to coincide with the center of rotation of the ball joint 18.

Thus, the wall suction unit 5 is rotatable with respect to the leg frame 10.

One ends of the parallel holding mechanisms 20 and 20 are connected to the branch arm portions 17a and 17a of the V-arm 17 and the ends thereof, respectively.

As shown in FIG. 4, the parallel holding mechanism 20 is
It is composed of a flexible tube-shaped outer cable 21 and an inner cable 22 inserted into the outer cable 21. The outer cable 21 has a leg frame 10 at one end.
Is fixed to the tip of the spline shaft 11, curved inside the body 2, and the other end is fixed to the surface of the body 2. Also,
The inner cable 22 has one end fixed to the tip of the support rod 12, penetrates the outer cable 21, and the other end is fixed to the tip of the V arm 17 of the wall suction unit 5. Inside the body 2, the outer cable 21 in which the inner cable 22 is inserted can freely bend.

In this way, the wall suction unit 5 is provided with the two sets of parallel holding mechanisms 20 and 20 arranged in different planes, respectively, and thus the body 2
Are linked to.

Next, the operation of the leg mechanism 3 thus configured will be described.

FIG. 6 is an explanatory diagram for explaining the principle of the basic structure of the leg mechanism 3.

As shown in this figure, it is assumed that the support rod 12 is connected to the body 2 by a universal joint at the origin O and extends in the Z-axis direction. Further, expansion actuators 6 ₁ of three, 6 _2, 6 _3, points on the X axis Q and Y
It is rotatably connected to the body 2 at points R and S on the axis, and rotatably connected to the leg frame 10 at points A in the XZ plane and points B and C in the YZ plane. It is assumed that

In this state, when the actuator 6 ₁ is expanded / contracted and its length is changed, the leg frame 10 constrained by the remaining actuators 6 ₂ and 6 ₃ is moved to those actuators 6 ₂ and 6 ₃
Rotate around the Y-axis with the plane containing. Therefore, the attachment point P of the suction cup 15 to the leg frame 10
Also rotates around the Y axis. In addition, the actuator 6 ₂ , 6
_{When one of the 3} is extended and the other is contracted, the leg frame 10 rotates about the X axis and the point P also rotates about the X axis. And the three actuators 6 ₁ , 6 ₂ , 6 ₃
When the legs are simultaneously expanded and contracted, the leg frame 10 moves along the axis of the support rod 12, and the point P moves in the Z-axis direction. During this period, the leg frame 10 is splined to the support rod 12, so a plane including each arm of the leg frame 10,
That is, the angle formed by the support rod 12 and the plane including the points A, B, and C is always kept constant. Therefore, the three-dimensional position of the point P is uniquely determined.

During this movement, a moment is generated between the arms of the leg frame 10, but all the moment is supported by the support rod 12, so that no bending moment acts on the actuators 6 ₁ , 6 ₂ , 6 ₃ . If three actuators 6 ₁ , 6 ₂ ,
If 6 ₃ can be rotatably connected to the leg frame 10 at one point, the moment generated between each arm can be reduced to zero, but such connection is mechanically extremely difficult. Is. Therefore, in order to internal moment is suppressed to be generated, the length of each arm of the leg frame 10, the connecting portion of the end of the actuator 6 _and 62, 6 ₃ mutually mechanically interfere Be as short as possible within the limit.

Thus, in this leg mechanism 3, since the three actuators 6 _1, 6 _2, 6 ₃ by 3 degrees of freedom is given, it is possible to move the suction cup 15 to spatially arbitrary position. Since the three actuators 6 ₁ , 6 ₂ and 6 ₃ are arranged in parallel or at a small angle, if they are oriented in the direction of gravity, the load applied to the leg mechanism 3 will be those three actuators. It is almost evenly supported by 6 ₁ , 6 ₂ and 6 ₃ . Moreover, the bending moment acting on the leg mechanism 3 is transmitted from the leg frame 10 to the support rod 12 and is supported by the body 2 at the origin O. Therefore,
Each actuator 6 ₁ , 6 ₂ , 6 ₃ has only to bear the load in the axial direction, and can have low output and light weight.

By the way, according to the leg mechanism 3, the position of the point P in the three-dimensional space is determined as described above, but the posture of the leg frame 10 changes with the change of the position. Therefore, in this state, for example, the leg frame 10
Is inclined with respect to the YZ plane, the suction cup 15 that has been oriented in a constant direction with respect to the YZ plane is inclined, which is an obstacle to normal walking motion. Therefore, a space parallel holding mechanism 20 for always keeping the posture of the suction cup 15 attached to the leg frame 10 the same as the posture of the body 2 is introduced.

FIG. 7 is an explanatory view for explaining the principle of the space parallel holding mechanism 20.

As shown in this figure, the support rod 12 is rotatably supported on the body 2 at a point O, and the wall suction unit 5 is attached to the leg frame 10 splined to the support rod 12 at a point P. It shall be rotatably supported. The point on the side of the tip of the support rod 12 away from the body 2 is K, and the point of the leg frame 10 near the body 2 is L.
The leg frame 10 is configured so that the distance between the leg frame 10 and the body 2 can be changed by a telescopic actuator (not shown).

In this state, for example, bring the leg frame 10 close to the body 2 and
If O and P are contracted, the distance between points K and L will increase.
On the contrary, when the distance between the points O and P is widened, the points K and L come closer to each other. The sum of the amount of change in the interval between O and P and the amount of change in the interval between points K and L is always constant.

That is, OP + KL = constant.

Therefore, the outer cable is connected between the point L and the point M on the body 2.
The inner cable 22 is provided between the point K and the point N on the wall suction unit 5 through the outer cable 21, and the distance between the points O and M is equal to the distance between the points P and N. To do.

By doing so, since the total length of the inner cable 22 is constant, the length of the portion exposed from the outer cable 21 is also constant, and KL + MN = constant.

Therefore, if OP = MN is set initially, the relationship is maintained no matter how the interval between the points O and P changes. And
Since OM = PN, the quadrangle OMNP is a parallelogram. As a result, even when the leg frame 10 pivots around the point O together with the support rod 12 and moves along the axis of the support rod 12, the wall surface suction unit 5 is always kept parallel to the body 2. It will be.

In this way, the parallel holding mechanism 20 is provided with the two cables 2
Since it is composed of 1,22, it is extremely lightweight, it occupies a small space, and can operate smoothly. If the inner cable 22 may sag, the spring 23 may be attached to the side opposite to the fixing point N of the inner cable 22 as shown in FIG. Further, a pair of such parallel holding mechanisms 20 may be provided on both sides of the point P.

As shown in FIG. 3, the leg frame 10 of the leg mechanism 3 is shown.
The V-arm 17 of the wall suction unit 5 attached to the main body 2 via the universal joint 19 is connected to the body 2 by the pair of parallel holding mechanisms 20 and 20 thus configured. Moreover, the parallel holding mechanisms 20 and 20 are arranged in different planes. Therefore, the leg frame 10 is 3
The V-arm 17 is always kept in parallel with the surface of the body 2 even when performing a dimensional movement. That is, no matter how the leg frame 10 tilts, the suction cup 15 urged by the ball joint 18 and the spring 14s to always point in the same direction with respect to the V-arm 17 always faces in a fixed direction. become. As a result, when walking on the flat wall surface 4, the suction cup 15 can be always opposed to the wall surface 4, and a smooth and stable walk can be performed.

In this case, since the suction plate 15 is attached via the ball joint 18, it is sufficient that the suction plate 15 is kept substantially parallel to the wall surface 4, and the parallel holding mechanism 20 does not need to be strict. Therefore, the fixing points of the cables 21 and 22 may have some errors.

As shown in FIGS. 1 and 2, when the walking robot 1 having four sets of the leg mechanisms 3 ascends the vertical wall surface 4, the body 2 is moved as close to the wall surface 4 as possible.
The leg mechanisms 3, 3, ... Are arranged substantially in the direction of gravity by unfolding vertically. Therefore, the three telescopic actuators 6 forming each leg mechanism 3 are also arranged substantially in the direction of gravity. Then, walk with a crawl gait, a trot gait, or a paced gait.

In the case of a crawl gait, the remaining one set of leg mechanisms 3 is returned with the three sets of leg mechanisms 3 adsorbed on the wall surface 4, the leg mechanisms 3 are adsorbed on the wall surface 4, and then another One set of leg mechanism 3
Repeat the procedure of returning to. In that case, the self-weight of the robot 1 is supported by the three sets of leg mechanisms 3 attracted to the wall surface 4. The load applied to each leg mechanism 3 is evenly shared by the three telescopic actuators 6. Therefore, the robot 1 is always driven by a total of nine actuators 6, and even if the output of each actuator 6 is small, a sufficient output can be obtained as a whole. Thus, the drive system has a high output / weight ratio.

Since a large output is obtained by each leg mechanism 3 in this way, it is also possible to take a trot gait or a pace gait that simultaneously restores two diagonally paired leg mechanisms 3. In that case, the suction mechanism 15 can be held in parallel with the wall surface 4 as described above even in the leg mechanism 3 that is returning, and can be returned in a floating state where it is almost in contact with the wall surface 4, so that efficient walking can be performed. You can And by making such a trot gait or pace gait,
Higher speed movement is possible.

According to such a wall-walking robot 1, it is possible to move on the vertical wall surface 4 having the large protrusion 4a as shown in FIG. When overcoming the protrusion 4a, each leg mechanism 3 may be pivoted with respect to the body 2 to move the body 2 away from the wall surface 4. At this time, the leg mechanism 3
Will make a large angle to the direction of gravity, but walking in such a state does not require high speed, so
It is not necessary to increase the output of each actuator 6 on purpose.

Further, as shown in FIG. 9, it is possible to move from the vertical wall surface 4 to the ceiling 4b. In that case, the same figure (A)
After the body 2 is slightly separated from the wall surface 4 as shown in Fig. 1 and the upper pair of leg mechanisms 3 are attached to the ceiling 4b, the same figure (B).
While tilting the fuselage 2 as shown in
The pair of leg mechanisms 3 is attached to the ceiling 4b. Then, as shown in FIG. 3C, the remaining two sets of leg mechanisms 3 are sequentially attracted to the ceiling 4b. Thereby, the robot 1 is completely moved from the vertical wall surface 4 to the ceiling 4b. Ceiling 4b
Then, the robot 1 walks in a state in which the body 2 is far away from the ceiling 4b so that the leg mechanisms 3 are oriented in the direction of gravity.

During the operation shown in FIG. 9 (A), the suction unit 5
Since the suction plate 15 of is held almost parallel to the wall surface 4,
When the leg mechanism 3 is attracted to the ceiling 4b, the suction plate 15 makes a large angle with respect to the ceiling 4b, but the suction plate 15 is only biased by the spring 14s.
Since it is rotatably supported by the ball joint 18, by adjusting the approaching direction to the ceiling 4b or tilting the body 2, it is possible to surely attract the surface to the ceiling 4b that makes a large angle. .

Similarly, as shown in FIG. 10, it is also possible to move across orthogonal wall surfaces 4c, 4d such as the corners of a building.

In the above embodiment, the spline shaft 11 is integrally provided on the leg frame 10, and the support rod 12 is fitted to the spline shaft 11. However, the support rod 12 is the spline shaft and the leg frame The 10 may be spline-fitted. In addition, these leg frames 10
The support rod 12 and the support rod 12 can be supported by a simple slide mechanism including a guide rail and rollers.

The number of leg mechanisms 3 attached to the robot 1 may be any number as long as it is two or more. From the viewpoint of adaptability to the environment, the larger the number of legs, the better. However, the number of legs should be small in order to simplify the mechanism. Therefore, the number of legs is determined according to the function required of the robot 1.

In addition, the three-dimensional motion mechanism according to the present invention can generate a strong supporting force in the direction of gravity by means of the three expansion and contraction actuators, and also has the freedom of movement in the horizontal direction. By providing a holding mechanism, the holding mechanism can be kept parallel to the base body at all times, and therefore, the present invention can be applied to various things other than the leg mechanism 3 of the wall-walking robot 1 as in the above embodiment.

FIG. 11 shows an embodiment applied to a manipulator of the type suspended from the ceiling.

The arm mechanism 31 of the manipulator 30 is configured similarly to the leg mechanism 3 of the above-described embodiment. That is, three telescopic actuators 32 and one support rod arranged in parallel.
It has 33 and. The base ends of the actuator 32 and the support rod 33 are rotatably connected to a ceiling 34 that is a base. The support rod 33 also has a free end frame 35.
Is slidably supported, and the tip of the actuator 32 is rotatably connected to the free end frame 35.
A gripper 36, which is an effector unit, is rotatably supported by the free end frame 35, and is kept parallel to the ceiling 34 by the parallel holding mechanism 37, that is, horizontal.

In the manipulator 30 configured in this way, since the finger of the gripper 36 always faces downward, the object 38 placed on the support base or the like can be reliably gripped. Since the load is dispersed and supported by the three actuators 32, a strong supporting force can be obtained. Further, since the arm mechanism 31 can be moved in the three-dimensional space, the object 38 can be moved to an arbitrary position. When it is required to change the direction of the object 38 in the horizontal plane, the gripper 36 may be given a degree of freedom of rotation about the vertical axis.

In addition, FIG. 12 shows an embodiment of a carrying device to which the three-dimensional movement mechanism according to the present invention is applied.

In the carrier device 40, the supporting legs 41 are the same as the leg mechanism 3 or the arm mechanism 31 of the above-described embodiment. The support leg 41 is rotatably supported on a floor 42 which is a base body, and a support base 43 which is an effector unit is attached to the upper end of the support leg 41. The support 43 has a parallel holding mechanism 44.
It is held parallel to the floor 42 by.

According to such a transport device 40, the load of the object 45 placed on the support table 43 is dispersed and supported by the three expansion / contraction actuators arranged along the direction of gravity. Therefore, even if the output of each actuator is small,
Can support 45. Then, by expanding and contracting the actuator, the support base 43 can be moved in the three-dimensional space while maintaining the horizontal state. Thus, the transport device 40 capable of transporting the heavy object 45 three-dimensionally is obtained.

The present invention can also be applied to a Stuart platform or the like when position determination is important and posture determination is not so important.

(Effect of the Invention) As is clear from the above description, according to the present invention, three degrees of freedom are provided by three telescopic actuators arranged in parallel or at a small angle, By arranging each of the actuators so that the direction of gravitational force is substantially present during the operation of, the large output can be obtained as a whole even if the output of each actuator is small. Then, the free end frame supported by those actuators is slidably fitted to the support rod connected to the base body through the universal joint, and the rotation with respect to the support rod is restricted. Not only the three-dimensional position of the effector unit attached to the free end frame is uniquely determined, but also the moment acting on the three-dimensional movement mechanism is supported by the supporting rod. Therefore, each actuator only needs to share the load in the axial direction, and the actuator can be reduced in weight and size.

In this way, a three-dimensional motion mechanism having a high output / weight ratio can be obtained.

[Brief description of drawings]

FIG. 1 is a schematic front view showing an embodiment of a wall-walking robot using a three-dimensional motion mechanism according to the present invention as a leg mechanism in a state in which a vertical wall surface is elevated, and FIG. 2 is a side view thereof. FIG. 3 is a perspective view showing a leg mechanism of the robot, FIG. 4 is a vertical side view of the leg mechanism, and FIG. 5 is an enlarged vertical side view showing a wall suction unit portion of the leg mechanism. The figure is an explanatory view showing the basic structure of the leg mechanism, Fig. 7 is an explanatory view showing the principle of the parallel holding mechanism used in the leg mechanism, and Fig. 8 is the wall walking of Figs. FIG. 9 is a schematic side view showing a state in which the robot moves up a vertical wall surface having a large protrusion. FIG. 9 is a schematic side view showing a state in which the robot moves from the vertical wall surface to the ceiling. The state when the robot moves across a corner of a building 11 is a schematic side view showing an embodiment in which the three-dimensional movement mechanism according to the present invention is applied to a manipulator, and FIG. 12 is an embodiment in which the three-dimensional movement mechanism according to the present invention is applied to a conveying device. It is a schematic side view which shows. 1 ... Wall walking robot, 2 ... Body (base) 3 ... Leg mechanism (three-dimensional motion mechanism), 4 ... Wall surface 5 ... Wall surface adsorption unit (effector unit) 6 ... Telescopic actuator 8,9 ... … Ball joint 10 …… Leg frame (free end frame) 11 …… Spline shaft, 12 …… Support rod 13 …… Universal joint 14 …… Support arm, 15 …… Suction plate 17 …… V arm, 18 …… Ball Joint 19 …… Universal joint 20 …… Parallel holding mechanism 21 …… Outer cable 22 …… Inner cable 30 …… Manipulator 31 …… Arm mechanism (three-dimensional motion mechanism) 32 …… Extension actuator 33 …… Support rod, 34… … Ceiling (base) 35 …… Free end frame 36 …… Gripper (effector unit) 37 …… Parallel holding mechanism 40 …… Conveyor 41 …… Support legs (three-dimensional motion mechanism) 42 …… Floor (base) 43 … Support stand (effector unit) 44 ...... parallel holding mechanism

Claims (2)

[Claims] 1. A support rod having a base end connected to a base body through a universal joint, and a support rod fitted to the support rod so as not to rotate about its axis but slidable in the axial direction. The supported free-end frame is rotatably connected to the base at three points which are not on the straight line of the base body, and the tip is freely rotatable at the three points which are not on the straight line of the free-end frame. A three-dimensional motion mechanism, comprising: three telescopic actuators connected to each other and arranged in parallel or at a small angle to each other, wherein an effector unit is attached to the free end frame. 2. The effector unit is rotatably attached to the free end frame, and the effector unit is provided on the base body via two sets of parallel holding mechanisms respectively arranged in different planes. The parallel holding mechanism has a flexible outer cable whose one end is fixed to a point of the free end frame near the base body and the other end is fixed to the base body, and is inserted into the outer cable. 3. An inner cable, one end of which is fixed to a point of the support rod separated from the base body, and the other end of which is fixed to the effector unit. Dimensional movement mechanism.